1. Field of the Invention
This invention relates to a strapped fastener assemblage used with an automatic fastener driver for continuously driving screws, nails and the like.
2. Description of the Prior Art
Heretofore, various types of strapped fastener assemblages used with an automatic fastener driver have been developed. These types are classified into three groups as shown in FIGS. 29 to 35.
A first strapped fastener assemblage 1 as shown in FIGS. 29 and 30 comprises two parallel connecting wires 2 and a plurality of fasteners, i.e., screws 3 crossing the wires 2 and arranged with a predetermined spacing along the axes of the wires 2. Points of contact 4 between the threaded portion 3a of each screw 3 and the wires 2 are joined by spot welding.
A second strapped fastener assemblage 5 as shown in FIGS. 31 and 32 comprises a pair of adjacent connecting straps 6 made of a synthetic resin and a plurality of screws 3 retained between the connecting straps 6 and arranged with a predetermined spacing along the axes of the connecting straps 6. The connecting straps 6 form cylindrical screw retainers 8 each of which surrounds the threaded portion 3a of a screw 3, by means of a pair of adhesion portions 7 formed in front and rear of each screw 3 in the axes of the connecting straps 6.
A third strapped fastener assemblage 9 as shown in FIGS. 34 and 35 comprises a pair of adjacent connecting straps 10 made of paper and a plurality of screws 3 retained between the connecting straps 10 and arranged with a predetermined spacing along the axes of the connecting straps 10. The connecting straps 10 form cylindrical screw retainers 11 each of which surrounds a threaded portion 3a of a screw 3, by means of a pair of adhesion portions 7 formed in front and rear of the screw 3 in the axes of the connecting straps 10.
The conventional strapped fastener assemblages 1, 5 and 9 entail certain problems. As described above, the first strapped fastener assemblage 1 with the connecting wires comprises the screws 3 including the threaded portions 3a adjoined to the connecting wires 2 by means of the spot-welded joints 4. Thus, the spot-welded joints 4 cannot clearly be detached from the threaded portion 3a when the automatic fastener driver drives each screw 3. Fragments 2a of the wires 2 and fragments of the spot-welded joints 4 remain on the threaded portion 3a. These fragments 2a cause the threaded portions 3a to be damaged, thus blocking a secure fastening operation of each screw 3. The spot-welded joints 4 of the strapped fastener assemblage 1 require some troublesome work. Large spot-welded joints 4 cause their poor detachment from the threaded portions 3a. On the other hand, small spot-welded joints 4 cause the screws 3 to be readily detached from the connecting wires 2 when the strapped fastener assemblage 1 is in an inoperative position.
As described above, the second strapped fastener assemblage 5 with the connecting straps made of a synthetic resin retains each screw 3a within each screw retainer 8 defined by the adhesive portions in the two connecting tapes 6. Thus, when the automatic fastener driver drives the screws 3, the connecting straps 6 are broken into small fragments 6a which remains in a fastener magazine of the automatic fastener driver. Since the remaining fragments 6a may block continuous supply of the strapped fastener assemblage 5 into the fastener magazine, it is difficult to accurately drive the screws 3.
In addition, since the front and rear edges of each fastener retainer 8 of the strapped faster assemblage 5 include the adhesive, a component of the adhesive will chemically erode the surface of the threaded portion 3a of the screw 3 to produce rust on the surface with passage of time. The production of the rust will damage the value of commodity of the strapped fastener assemblage and will fatally damage the screws. Therefore, if the problem of the production of the rust is not resolved the service life of the screw is reduced.
The third strapped fastener assemblage 9 with the straps made of paper includes the adhesive similarly to the second strapped fastener assemblage 5. In fact, the third strapped fastener assemblage 9 increases production of rust since the paper straps have a hygroscopicity higher than the straps made of the synthetic resin in the strapped fastener assemblage 5.